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United States Patent |
5,591,375
|
Lott
,   et al.
|
January 7, 1997
|
Antifreeze compositions and uses
Abstract
This invention relates to antifreeze multi-component compositions which are
combined substantially simultaneous with their application to target
surfaces. More specifically, component part A is a mixture which includes
some percentage of polysaccharides which contain acid functional groups
and a gelatinous material while part B contains at least one polyvalent
cation and a solvent. Part A components and part B components are kept
separate until ready for application at which time part A and part B
components are sprayed onto the intended surface and mixed together in the
presence of pressurized air to produce a gel which will adhere to the
surface being coated and react to form a resilient coating. Uses for the
compositions of this invention include coating aircraft parts such as
wings to prevent or remove icing while the plane awaits takeoff. At
takeoff, the composition which may contain a release agent, will quickly
sluff off the treated parts of the aircraft. Other uses for the tailored
compositions of this invention include coating the inside of railroad cars
and trucks used for carrying such materials as coal and mineral ores.
Inventors:
|
Lott; James A. (910 W. 3rd, Maryville, MO 64468);
Kizer; David V. (4112 N. 31st, St. Joseph, MO 64506)
|
Appl. No.:
|
410415 |
Filed:
|
March 27, 1995 |
Current U.S. Class: |
252/70; 106/13; 106/14.05; 106/14.11; 106/14.13; 252/73; 427/221 |
Intern'l Class: |
C09K 003/18; C09K 005/00 |
Field of Search: |
252/70,73
106/13,14.05,14.11,14.13
427/221
|
References Cited
U.S. Patent Documents
2101472 | Dec., 1937 | Korman | 134/27.
|
2436146 | Feb., 1948 | Kleinicke | 252/88.
|
4066796 | Jan., 1978 | McKee | 426/302.
|
4222740 | Sep., 1980 | Bohrn et al. | 8/448.
|
4388203 | Jun., 1983 | Nimerick et al. | 252/70.
|
4426409 | Jan., 1984 | Roe | 427/221.
|
4439337 | Mar., 1984 | Nimerick et al. | 252/70.
|
4698172 | Oct., 1987 | Tye et al. | 252/70.
|
5079036 | Jan., 1992 | Roe et al. | 427/212.
|
5089606 | Feb., 1992 | Cole et al. | 536/54.
|
5135674 | Aug., 1992 | Kuhjek et al. | 252/70.
|
5147648 | Sep., 1992 | Bannert | 424/435.
|
Other References
Research Disclose Apr. 1985 '25246 "Aircraft de-icer".
Research Disclosure, Apr. 1985, "Aircraft De-Icer", No. 25246, p. 201.
|
Primary Examiner: Lieberman; Paul
Assistant Examiner: Kopec; M.
Parent Case Text
This is a continuation of application Ser. No. 07/950,934 filed on Sep. 24,
1992, now abandoned.
Claims
We claim:
1. A multi-component antifreeze composition comprised of:
part A comprised of a water containing solution of an alginic acid
composition containing acid functional groups, the alginic acid
composition being selected from the group consisting of sodium, potassium
and ammonium salts of alginic acid, and a separate,
part B comprised of a water containing solution of a water containing
solution of a polyvalent cation salt selected from the group consisting of
soluble calcium, aluminum and iron salts,
the alginic acid composition being present in part A in an amount between
about 0.1 to 20% by weight, and the polyvalent cation salt being present
in part B in an amount between about 0.001 and 30% by weight, and wherein
part A of the composition further includes about 10% by weight to about
50% by weight of a corrosion control agent selected from the group
consisting of calcium carbonate, dolomite and magnesium carbonate,
part A and part B being effective to form a releasable gel film on a
surface preventing ice from adhering to the surface and permitting ready
removal of an ice containing material from the surface.
2. The composition of claim 1 wherein the alginic acid salt of part A is
the sodium salt.
3. The composition of claim 1 wherein the soluble polyvalent cation salt of
part B is a calcium salt.
4. The composition of claim 1 wherein the part A also contains a material
selected from the group consisting of gelatin, pectin, modified starch,
cellulosic materials and salts and combinations thereof.
5. The composition of claim 1 wherein the part A includes propylene glycol.
6. The composition of claim 1 wherein part B includes propylene glycol.
7. The composition of claim 1 where in the corrosion control agent is
dolomite.
8. The composition of claim 1 where in part B contains a corrosion control
agent selected from the group consisting of calcium carbonate, dolomite
and magnesium carbonate.
9. The composition of claim 8 where in the corrosion control agent is
dolomite.
10. The composition of claim 1 wherein the alginic acid composition of part
A is present at between about 1-10% by weight and is tale sodium salt of
alginic acid, wherein the polyvalent cation salt of part B is present at
between about 0,006 and 15% by weight and is a soluble calcium salt, and
where part B includes dolomite as a corrosion inhibitor, the dolomite
being present at between about 15 and 30% by weight of part B, wherein the
solution of part A contains between about 20-99% by weight water and
between about 0.1 and 50% by weight propylene glycol, based on the weight
of solvent, and wherein the part B solution contains between about 20-99%
by weight water and between about 1 and 99% by weight propylene glycol
based on the weight of solvent.
Description
FIELD OF THE INVENTION
The invention relates to environmentally responsible multipart antifreeze
chemical compositions which avoid the use of ethylene glycol or alkaline
earth halides for use primarily in the prevention of ice related
complications in the transportation and storage of particulate materials
such as coal and iron ore, and the de-icing of aircraft components prior
to take-off.
BACKGROUND OF THE INVENTION
The complications associated with the transportation and storage of
particulate materials which can freeze and clump together during the
colder periods of the year has become a major commercial problem. Such
materials are transported and stored primarily in open vehicles and
containers, accessible to potential ice generating precipitation including
rain, sleet and snow. The problem is particularly acute in transportation
of coal, iron ore and other minerals in open rail cars and trucks. As the
loaded cars and trucks are moved across the country, the material in the
zone immediately adjacent the outer walls of the vehicles gets cold faster
than the main body of material. Moisture subsequently condenses in this
zone and the material begins to aggregate as the moisture freezes, acting
as a cement. This condensation, coupled with the moisture from rain, sleet
and snow which tends to collect adjacent to the container walls causes a
defined layer of material-incorporated ice to harden adjacent to and
become attached to the walls. As much as 20 percent of the material may
remain frozen in the car. The purchaser of the material has ordered 100
percent and received 80 percent Furthermore, the shipper has to pay to
haul that 20 percent of the material back to the mining site. If the
material freezes in uneven weight distributions, which it often does, the
shipper cannot move the car until they have removed the rest of the
material in order to keep the cars balanced and avoid potential
derailments. This wall-adhering frozen portion therefor makes material
unloading difficult through the normal automated procedures and requires
people with chipping tools to enter the partially unloaded containers to
manually remove the remaining iced layer stuck on the walls.
A problem also arises when moisture leaches corrosive compounds from the
contained particulate materials, even at temperatures at and below
freezing. Storage containers and vehicles such as rail cars and truck beds
are made of iron containing metals which tend to rust and corrode
excessively because of this corrosive moisture in contact with the walls.
This corrosive action thereby shortens the expected lifetime of such
containers and vehicles.
The compositions of this invention are also useful in de-icing and
protecting external aircraft components from freezing during the period of
time surrounding take-off. During severe cold weather conditions, the
wings and body portions of aircraft will become coated with ice, sleet and
snow and such build-up must be removed from the aircraft prior to
take-off. In fact, plane crashes have occured because the build-up was
sufficient to prevent the aircraft from gaining proper altitude after
take-off. Various systems are presently used to prevent such build-ups and
to remove layers of ice, sleet and snow immediately prior to take-off.
However, no completely satisfactory system has been developed.
The prior art details several attempts at correcting these problems. Some
inventors have attempted to correct the problems only after the
particulate material is already frozen to the container walls. U.S. Pat.
No. 4,388,203 discloses compositions and methods for melting already
frozen material by applying de-icing compositions to the surface of
particulate materials such as coal. These compositions also may be used on
frozen surfaces such as rail cars to thaw accumulated frozen water. This
is inefficient as one would have to wait for each container of material to
thaw at every transfer point before unloading and use.
Other inventors have treated the materials themselves prior to loading into
the vehicles or storage containers. U.S. Pat. No. 4,426,409 discloses
freeze protection polymer systems for use in spraying particles such as
coal to reduce the cohesive strength of such particles. U.S. Pat. No.
5,079,036 discloses a brine freeze control agent which is applied to
particulate materials such as coal or mineral ores to inhibit freezing
aggregation. This is uneconomical when one considers the millions of tons
of such materials shipped every year and the additional cost involved in
treating the necessary materials.
A few inventors have attempted to solve the problem through preventative
treatment of the containers prior to the addition of the particulate
material. In Nimerick U.S. Pat. No. 4,439,337, a viscous mixture is
applied to the metal surface before loading of the materials in order to
freeze proof those surfaces. Other attempts have been made to control and
inhibit the freeze agglomeration of particulate materials during
transportation and all such attempts have limitations ranging from
difficulty of application to low cost-performance ratios. Many of these
solutions contain ethylene glycol, sodium chloride and other substances
which require special disposal methods or adversely affect the
environment. The aircraft anti-icing fluid in U.S. Pat. No. 4,698,172 is
an ethylene glycol solution thickened with gel forming carrageenans.
SUMMARY OF THE INVENTION
This invention relates to environmentally responsible antifreeze
multi-component compositions which are combined substantially simultaneous
with their application to the target surfaces. The use of environmentally
detrimental materials such as ethylene glycol and alkaline earth halides
are avoided and instead, biodegradable ingredients are utilized. More
specifically, component part A is a mixture which includes some percentage
of polysaccharides which contain acidic functional groups, and gelatinous
materials in at least one solvent while component part B contains
polyvalent cations and at least one solvent.
Part A and part B are kept separate until the time for application, at
which time part A and part B are preferably sprayed sequentially and upon
mutual contact produce a gel which adheres to the surface and reacts to
form an antifreeze film. Other known methods of application, such as
painting, may be used.
Other elements such as surfactants and non-reactive diluents are added to
meet a particular utilization requirement. Of particular importance, a dye
in the coating mixture provides a more visible product. Also, an additive
can be incorporated into the antifreeze composition to neutralize the
corrosive agents released by some materials. Uses for the tailored
compositions of this invention include coating the inside of railroad
cars, trucks, and vessels used for the transportation and storage of
particulate materials.
Uses for the compositions of this invention also include coating aircraft
parts such as wings to prevent or remove icing while the plane awaits
take-off. At take-off, the composition which may contain a release agent,
will quickly sluff off the treated parts of the aircraft. A dye added to
the composition enables the pilot to more quickly inspect aircraft icing
conditions prior to and during take-off.
DETAILED DESCRIPTION OF THE INVENTION
The invention relates to environmentally preferred multi-part antifreeze
compositions applied in an innovative, rapid and economical manner, to
particulate material transporting devices such as railroad cars, trucks,
barges, wheel barrows and conveyor belts, as well as storage containers.
These biodegradable and nontoxic antifreeze compositions assist in
particulate material removal at and below freezing temperatures by
preventing the formation of high strength ice crystals between the
contained material and the walls of the devices.
The accumulation of ice on aircraft while awaiting take-off is a safety
hazard. The decision to take-off under icing conditions has been left to
the discretion of the pilot. Unfortunately, the pilot's main method of
making that decision has been through personal inspection which has been
often flawed. This invention involves a method of preventing ice build-up
over longer periods of time and assists the pilot in the decision to
take-off or reapply the de-icing treatment by providing a visual means of
determining if ice build-up is a problem. The invention also may be used
to remove an ice accumulation already on the aircraft.
Antifreeze Formulations
The compositions of this invention are used to coat the sides of railroad
cars and other vehicles or containers prior to the introduction of
particulate material, to prevent ice bonding the material to the vessel
surfaces. Initially the several parts of the composition are applied onto
the sides of a railroad car, for example. When the two component parts
react and cure, they form a thin gel film, the properties of which can be
formulated to range from water soluble to water insoluble by controlling
the amount of crosslinking of the component elements. The gel film
prevents ice from adhering to the vessel surfaces because the film behaves
as an antifreeze, preventing any water in contact with the film from
forming ice crystals. In addition, the texture of the coating prevents any
ice crystals that do form from achieving a strong physical bond with the
more porous metal surface. Although ice might still form and bond with the
film, the bond between the ice containing material and the film will not
have sufficient tensile strength to prevent the material from routinely
falling from the vessel when the vessel is unloaded under normal
procedures.
The antifreeze compositions include multiple components which are
separately applied to the surface. Individual component parts are
preferably kept separate before their application because the rapid
reaction between the components results in a semi-solid composition which
can not be applied in an easy manner incorporating a standard spray
apparatus.
The preferred antifreeze composition employs a two part multi-component
system. The combination of part A and part B forms a novel composition
with substantially improved characteristics over those of either
individual part. Part A includes at least one polysaccharide which
contains acid functional groups and a gelatinous material dissolved in at
least one solvent. Part A is a thick and viscous, semi-fluid gel,
especially at low temperatures, and by itself has antifreeze properties
which prevents the formation of ice crystals. The gels of this invention
have a freezing point dictated by the amount of water-soluble organic
compounds included in part A and part B, but preferably the gel will have
a freezing point of nearly minus 40 degrees Fahrenheit. The final gel
strength is dictated by the type and quantity of gelatin dissolved in part
A.
The greater the percentage of gelatin, the greater the gel strength and the
higher the temperature at which the mixture will completely set-up.
Gelatin reduces the vapor pressure of the composition formed and causes it
to remain pliable for a longer period of time. Gelatin is also impervious
to all but the strongest of acids. This is desirable because the strong
acids eluted from some particulate materials could react with some of the
polyvalent cations included in the antifreeze composition and reduce the
strength of the gel film.
The polysaccharides which contain acid functional groups useful in this
invention include, singly or a combination thereof, cellulosic materials
such as cellulose gum (carboxymethyl cellulose) and cation salts thereof,
including sodium, potassium, and ammonium salts; polyuronic acids such as
soluble alginic salts acid, pectins and cation salts thereof, including
sodium, potassium, and ammonium salts; and modified starches such as
oxidized starches and carboxylated starches, and cation salts thereof,
including sodium, potassium, and ammonium salts. These biodegradable
materials pose no known environmental problems.
Gelatinous materials include gelatin, collagen, and salts thereof or a
mixture of such materials. Materials such as these proteins are rapidly
degraded by environmental forces.
The polysaccharides which contain acid functional groups are effective at
levels ranging between about 0.1 percent to about 20 percent by weight but
preferably between about 0.1 percent to about 10 percent by weight. The
gelatinous material is added in the range of about 0.5 percent to about 20
percent by weight and the preferred range is between about 0.5 percent and
about 12 percent by weight.
Part A is generally dispersed in at least one solvent, preferably water or
organic glycols with low toxicity such as propylene glycol, or a plurality
of such compounds. The solvent of part A ranges between about 60 percent
and about 99 percent by weight, where the water amount ranges between
about 20 percent and 99 percent by weight and the organic element is
preferably between about 0.1 percent and about 50 percent by weight.
Part B contains gel stabilizing water soluble polyvalent cation salts in a
solvent. The gel stabilizing polyvalent cation salts include, for example,
salts of aluminum, calcium, iron, tin, chromium, and zinc, including
aluminum nitrate nonahydrate (Al(NO.sub.3).sub.3.9H.sub.2 O), calcium
acetate (Ca(OAc).sub.2), and ferric chloride hexahydrate
(FeCl.sub.3.6H.sub.2 O).
The solvent in part B is in part water or an organic glycol with low
toxicity such as propylene glycol, alkoxytriglycols, alkoxydiglycols or
hydroxyethyl pyrrolidone, and also contribute antifreeze properties to the
finished film.
The polyvalent cation concentration should range between about 0.001
percent and about 20 percent by weight and preferably between about 0.006
percent and approximately 15 percent by weight. The water portion of the
solvent ranges between approximately 20 percent and about 99 percent by
weight, whereas the organic element ranges between about 1 percent and
approximately 50 percent by weight.
The antifreeze compositions include single elements or a plurality of
elements, such as a plurality of polysaccharides which contain acid
functional groups or a plurality of polyvalent cation salts. Different
polysaccharides which contain acid functional groups form gels with
different properties when they contact polyvalent cations. A film
containing cellulosic material is a very smooth, even textured gel whereas
alginic acid containing gels provide a more rigid, uneven gel, though much
sturdier than a cellulose containing gel. Therefore, applications may
require a mixture of such acid containing polysaccharides to produce the
required consistancy. Similarly, different polyvalent metal cations salts
have different gel stabilizing properties and different costs, so often a
combination of such salts best form the properties needed for a particular
antifreeze composition gel application.
The two parts are applied in the following general method. In the preferred
practice, part A and part B are preferably placed in individual high
pressure spray units and sprayed under pressure to form a gel film surface
layer adjacent to and adhering to the surface of all craft components.
Preferrably the separate components are applied with sprayers but
mechanical methods of application including brushes, rollers, or
spreaders, alone or in conjunction with spraying, can be utilized to apply
some portion of the composition. Part A and part B are placed in separate
carboys connected to separate Powermate Pressure Wash, Model PW70- 1200,
pressure spray units from Coleman Powermate, Inc., Kearney, NE. The
original spray wands are replaced with a piece of steel pipe to which a
nozzle body and a flat spray tip (Model #730308, Spray System Co.,
Wheaton, Ill.) are secured via a nozzle cap. The carboys are placed higher
than the sprayers to prime and gravity feed the two units. The two spray
wands are secured by clamps to a length of 1".times.4" board to hold them
securely about 4 inches apart. The two spray tips are aligned parallel to
each other so the nozzle orifices are aligned vertical to the ground. The
supported spray wands are held approximately four feet from the surface to
be sprayed and produce a spray covering about a four foot wide area. The
pumps of the spray units are activated and the solutions are released in a
flat, fan-shaped fine spray mist. The spray heads are moved in a
horizontal motion to apply the compounds in such a manner that part A is
preferably applied slightly before part B in these antifreeze compositions
so that part A's gelatin formulation initially retains the acid containing
polysaccharides on the vessel walls for reaction with the crosslinking
polyvalent cations in part B to form a uniform gel on the surface. The
spray unit pressures used depend on the viscosity of part A and part B,
and range from approximately 40 psi to approximately 1200 psi, 250 psi to
350 psi is best, but about 300 psi is preferred. The effective flow rate
range of part A is between about 0.2 gallon per minute and about 1.75
gallon per minute but the preferred rate is about 0.5 gallon per minute.
The flow rate range for spraying part B is between about 0.1 gallon per
minute and about 1.8 gallon per minute with the preferred rate being about
0.2 gallon per minute. The wands are moved to apply a uniform layer of
antifreeze ranging between about 1/1000 inch and about 1/4 inch with the
preferred range being about 1/32 inch and about 1/8 inch thick.
Alternatively, the components are mixed in a single spray nozzle
substantially immediately prior to the outlet orifice so the mixing is
improved. The pressurized spray method of application, in addition to the
beneficial ease, speed and low cost properties, also produces a beneficial
air rich environment which assists oxidation of any reduced metal to
higher valency forms for improved reactions with the polysaccharides.
Gelatin, in combination with cellulose gum, pectin, alginic acid and other
polysaccharides, prevents the strong adhesion of frozen material to the
walls of a vessel, allowing easy material removal even in freezing
conditions. The invention in the form of a thin water insoluble gel will
be resistant to absorption by the material being transported. The water
insolubility of the gel also ensures that rain, sleet and snow which might
enter the container will not rinse the coating off the walls of the
container or render it ineffective for its intended protective antifreeze
purpose. The gelatin containing solution should be constantly agitated
prior to being applied to ensure the solution does not gel in the bottom
of the container. Although some gel may form during long term storage
prior to application, the gel is dispersed upon subsequent heating and
stirring.
The polyvalent metal salts in part B are also critical to the formation of
the gels. The polyvalent metal cation salts react with the high molecular
weight polysaccharides and proteins in part A and become intertwined,
resulting in a strong gel layer. Higher concentrations of such inorganic
salts rapidly form firmer, more water insoluble gels. Iron (III) appears
to be the best all around polyvalent ion for this application. Al (III)
tends to be cost prohibitive, and Ca (II), although cost effective, does
not yield as strong a gel as the others. Specifically, calcium ion cause a
gel to form initially, but an excess weakens the gel formed and causes it
to liquify. Other metal ions are either cost prohibitive or have adverse
environmental and health effects associated with their use.
Each of the components, part A and part B, may contain specific additives
which will be included based on the ultimate utilization of the
invention's compositions. For example surfactants, such as anionic
surfactant sodium lauryl sulfate, may be utilized to decrease the surface
tension of the solution to promote bubble formation in the resulting gel
film.
The following examples further illustrate the invention but are not to be
construed as a limitation on the scope of the invention. Example 1 details
the specific component elements and procedure for producing a composition
useful in protecting the surfaces of particulate material storage and
transportation vessels, such as rail cars. All percentages are calculated
on a weight percent basis.
EXAMPLE 1
______________________________________
Part A Part B
______________________________________
.5% cellulose gum 5% ferric chloride
.5% alginic acid (soluble salt)
50% propylene glycol
2% gelatin 45% water
47% water
50% propylene glycol
______________________________________
The weight of water equal to about 1/5 the calculated final weight was
heated to boiling and the predetermined mass of gelatin (275 bloom,
Dynagel, Inc., Calumet City, Ill.) was dissolved in this solution. The
solution was stirred for three minutes after complete dissolution was
apparent. The solution, while still warm, was diluted with the remaining
water. The solution was vigorously agitated using a device which created a
vortex into which the cellulose gum (7H, Aqualon Co., Wilmington, Del.)
was gradually introduced. There was a dramatic increase in the viscosity
noted during this procedure. A predetermined amount of alginic acid (heavy
viscosity grade, Meer Corp., North Bergen, N.J.) was introduced into the
solution, noting the conditions encountered dissolving the cellulose gum.
The solution appeared clear, but not necessarily colorless due to the
nature of the compounds being dissolved. The remaining quantity of
propylene glycol (Eastman Chemical, Kingsport, Tenn.) was added to the
vigorously stirred solution until the solution was homogeneous.
Part B was prepared by measuring out the appropriate amount of ferric
chloride hexahydrate and dissolving it in water. The quantity of the
polyvalent metal salt should be no less than about 1/16 the weight of the
combined polysaccharides used in part A. The water soluble antifreeze,
propylene glycol, was then added and the solution was stirred vigorously
for approximately twenty minutes to ensure complete and homogeneous
distribution of the polyvalent metal ion.
Part A was placed in a container which gravity fed into a high pressure
spraying machine (Coleman Powermate, Inc. model PW70-1200) capable of
providing at least about 100 psi at the nozzle, and the pump was primed.
Part B was then placed in a second container which gravity fed into a
second similar high pressure spray unit also capable of providing no less
than about 100 psi at the nozzle, and that pump was also primed.
The spray wands of the two spray units were aligned parallel to each other
so the nozzles were vertical to the ground. The supported spray wands were
held approximately four feet from the surface to be sprayed to produce
about a four foot wide spray. The pumps of the spray units were activated
substantially simultaneously and the solutions were released in a flat,
fan-shaped fine spray mist. The pressures used depended on the viscosities
of part A and part B, but about 300 psi was preferred. The spray heads
were moved in a horizontal motion to apply the compounds in such a manner
that part A was applied to the surface first and part B was substantially
immediately applied to part A, allowing the two components to mix and
react to form a uniform gel. The preferred flow rate of part A was about
0.5 gallon per minute. The preferred flow rate for spraying part B was
about 0.2 gallon per minute. The wands were evenly moved to apply a
uniform layer of antifreeze between about 1/32 inch and about 1/8 inch
thick.
Part A and part B reacted to form a gel which adhered to the surface to
which it was applied. Upon setting for a short period of time the gel
developed greater strength, became less fluid and more rigid. A gel with
sufficient strength developed after about twenty minutes.
Antifreeze and Corrosion Control-Two Component System
A problem arises during the freeze-thaw weather patterns experienced during
the transportation and storage of particulate materials, such as coal and
mineral ores. Moisture leaches compounds out of the materials, causing an
adverse corrosion related degradation of the vessels. Storage containers
and vehicles such as rail cars and truck beds are made of iron containing
metals which tend to rust and corrode excessively on contact with these
corrosive compounds. This corrosive action thereby shortens the expected
lifetime of such containers and vehicles. The problem is well known and
many unsuccessful attempts have been made to alleviate it. A corrosion
control agent is incorporated into the antifreeze formulation of this
invention not only to aid in the unloading of the vessels but also reduce
the corrosion caused by corrosive substances eluted from the particulate
materials.
A two component system which forms a water-insoluble, non-toxic,
biodegradable film or gel containing a corrosion control agent
homogeneously distributed throughout, prevents the corrosion which reduces
the life of railroad cars and other devices used to transport and store
potentially corrosive particulate materials.
Possible corrosion control agents include calcium carbonate, dolomite,
magnesium carbonate and other insoluble metal compounds which are able to
neutralize corrosive acids, yet are environmentally compatible with the
intended use of the contained material. The presence of calcium compounds
as corrosion control agents does not weaken the resulting antifreeze gels
as soluble calcium salts do when used in similar amounts as a polyvalent
cation source, because these agents are water insoluble and do not
interact with the gel-forming mixture.
The spray unit pressures will depend on the viscosity of part A and part B,
and range from approximately 40 psi to approximately 1200 psi, 250 psi to
350 psi is best, but about 300 psi is preferred. The effective flow rate
range of part A is held to be about twice that of part B because of the
desired concentration of the two parts and ranged between about 0.25
gallon per minute and about 1.75 gallon per minute, but the preferred rate
is about 0.5 gallon per minute. The flow rate range for spraying part B is
between about 0.1 gallon per minute and about 1.8 gallons per minute with
the preferred rate being about 0.2 gallon per minute. The spray wands are
moved to apply a uniform layer of antifreeze ranging between about 1/1000
inch and about 1/4 inch with the preferred range being between about 1/32
inch and about 1/8 inch thick.
The resulting gel film is impervious to all but the strongest of acids.
This is desirable because the strong corrosive acids eluted from the
transported material can react with the polyvalent cation to weaken the
gel film. Even if some gel film deterioration occurs, the exposed portion
of the gel layer provides for additional corrosion control agent to
neutralize the excess corrosive material, thereby arresting further
deterioration.
Corrosion control agents such as dolomite can be added to either or both
part A and part B although it is not soluble in either. The corrosion
control agents are included in the range between about 10 percent and
about 50 percent and preferably between about 15 percent and 30 percent.
Gelatinous materials are also added to either or both parts so that when
the gel is formed by the initial reaction the gelatin could begin to set
and form a more rigid film. Agitation is required during mixing and
application to maintain the gelatin and corrosion control agent in
solution. If the gelatin does gel during periods of inactivity, the gel
can be reversibly brought back into solution by heating the gel over its
melting temperature while agitating the solution.
The water insoluble nature of this gel, resulting from the gelatinous
material composition and the curing from the polyvalent metal cations,
serves two functions. The layer will not be easily washed off by
precipitation, nor will corrosive acids rapidly penetrate it to attack the
metal walls of the treated vessel.
A mixture of individual polysaccharides which contain acid functional
groups can be used in part A to modify the gel properties. A preservative
may be used in part A, e.g. 1% propylene glycol, to prevent attack by
bacteria and mold if polysaccharides other than cellulosic materials are
used. Other known preservatives may be used.
A specific formulation and procedure for application is included in example
2 below. The percentages are based on a total weight basis.
EXAMPLE 2
______________________________________
Part A Part B
______________________________________
.5% cellulose gum 5% ferric chloride
.5% alginic acid 47% water
1% gelatin 48% propylene glycol
34% water
34% propylene glycol
30% dolomite powder
less than 1% dye
______________________________________
Part A was prepared by first determining the weight of the total solution
to be prepared. Water equal to about 1/3 the total weight was heated to
boiling and the predetermined mass of gelatin was dissolved in this
solution. The solution was stirred for three minutes after complete
dissolution is apparent. The solution was vigorously agitated by using a
device which created a vortex into which cellulose gum was gradually
introduced. There was a dramatic increase in the viscosity noted during
this procedure. A predetermined amount of alginic acid soluble salt was
introduced into the solution, noting the conditions maintained for the
cellulose gum. The dye was introduced and the solution stirred vigorously
for a period of no less than about one hour to ensure the complete
dissolution of the solutes. At the end of this time the solution appeared
clear, but not necessarily colorless. The dolomite powder was introduced
to this solution slowly to ensure it did not lump and remained present in
solution in the same consistency as when first introduced. The propylene
glycol was slowly added and the solution was stirred for about an
additional 20 minutes to ensure homogeneity. The resulting solution was
stored after vigorous agitation.
Part B was prepared by dissolving the appropriate amount of ferric chloride
hexahydrate in water. The propylene glycol was added and the solution was
stirred for approximately 20 minutes. This solution was stored until ready
for use.
The composition components were applied through an apparatus similar to
that used in example 1. Part A was placed in a five gallon carboy and
raised about two feet above the spraying mechanism to gravity feed the
high pressure spray unit. The pump was primed and turned off. A magnetic
stirrer (Corning model PC-310) in the carboy as a means of agitation was
provided to ensure the dolomite and gelatin were homogeneous throughout
the system and did not accumulate or gel in the bottom of the container.
Part B was similarly hooked to gravity feed a second high pressure spray
unit, but no agitation means were needed since no dolomite was present in
part B.
The spray wand of each unit was snapped into a holder keeping them
approximately 4 inches apart. The units were energized substantially
simultaneously and the combined wand unit was moved in a horizontal motion
over the surface, starting at the top of the surface. The distance from
the surface to be covered was dictated by the pressure and design of the
spray. The usual distance was between about 3 feet to about 4 feet from
the surface. This allowed the solution to mix and react on the surface.
Part A was applied at about 0.5 gallon per minute under approximately 300
psi pressure and part B was applied about at 0.25 gallon per minute under
a similar pressure.
The dolomite was suspended in the viscous part A until it reacted with part
B at the surface to form the gel film. Any dolomite in part A was evenly
distributed at the surface and ready to react with any corrosive acids
eluting from the material being carried.
A simulation of the effect of a corrosive leachate on the above prepared
antifreeze gel containing a corrosion control agent was performed. A
solution of 1 molar sulfuric acid was applied to portions of the prepared
antifreeze composition gel. The sulfuric acid did not appear to affect the
texture or consistency of the gel film formed through the reaction of part
A and part B. The acid did not appear to dissolve any of the gel, but a
small amount of effervescence was evident as the surface corrosion control
agent neutralized the acid, emitting carbon dioxide in the process.
The insoluble nature of the antifreeze gel in both water and dilute acids,
plus the dolomite's reaction with any eluted acid was very effective in
reducing a previously bothersome and costly corrosion problem.
Aircraft Antifreeze and De-icing System
This invention also includes a method of protecting aircraft from the
effects of moisture condensing on the lifting surfaces, as well as ice
accumulation during periods of freezing rain, snow and sleet.
Specifically, the antifreeze composition prepared for protection of vessel
surfaces can be also applied to aircraft as antifreeze protection during
foul weather. In addition, this system employs a visible dye to assist the
pilot in determining if the plane is suitable for take-off or will require
additional de-icing. This visual aid, utilizing commercially available
dyes, such as commonly used food colorings, are capable of being observed,
even when dark to assist the pilot in determining the air worthiness of
his plane. Other useful commercially available dyes include natural dyes
and synthetic dyes capable of imparting easily visible color to the
antifreeze compositions.
These aircraft antifreeze films are prepared similar to that described for
the particulate material vessel antifreeze coating compositions described
above. These films present a slippery hard antifreeze surface which has a
tendency to repel water and ice. In addition, the polysaccharides which
contain acid function groups are not susceptible to freezing and will
inhibit ice crystals from forming. Also, the propylene glycol is mixed in
and suspended throughout the gel, presenting additional antifreeze
elements in a slow time release manner. Any precipitation or condensation
that hits the gel on the surface of the aircraft will partially dissolve
the gel film, forming a propylene glycol/water mixture which also serves
as an antifreeze.
The use of a dye in the gel composition provides an added safety factor,
although the visibility of the layer itself may be sufficient. Both the
pilot and the ground crew will be in a position to quickly inspect and
judge whether they had adequate anti-icing protection prior to take-off.
If the plane has been on the ground long enough for the gel to dissolve
and dissipate, it will be visually apparent through the lack of color. FAA
regulations leave the issue of additional applications of de-icer up to
the discretion of the pilot. This dye component will be an added safety
feature for all concerned. It is detectable using ultraviolet light
methods to aid in inspection during the night.
The composition will be applied with modified spray units (Powermate
Pressure Wash, Coleman Powermate, Inc., Kearney, Nebr.) identical to that
cited above. Part A and part B solutions are placed in carboys and placed
above the spraying unit to gravity feed the sprayers. The polyvalent
cations form a stabilized, more water resistant layer than found with the
foam composition in Example 3.
A water insoluble surfactant, such as dipropylene glycol monobutyl ether
(butyl Dipropasol solvent from Union Carbide), additionally prevents
moisture from penetrating to the wing surface. Other known commercially
available surfactants will work in this invention. The surfactants also
act as release agents, encouraging the gel to slide off the wings during
take-off. If one is unsure about its ability to shear during take-off,
alternatively it can be physically removed such as by using high pressure
air prior to take-off.
Alternatively, the invention includes an antifreeze and de-icer foam
composition intended for use as an aircraft de-icer that produces a thick
water soluble foam, unlike the previously detailed gel formed with
polyvalent metal cation crosslinking. In addition, this foam composition
includes significant differences in the method of applying the parts to
the aircraft surfaces.
The multi-component compositions include part A consisting of
polysaccharides which contain acid functional groups, gelatinous materials
and surfactants dissolved in a solvent system. Part B consists of an
antifreeze solution consisting mainly of hydroxy containing organic
compounds and a food color dye.
The polysaccharides which contain acid functional groups useful in this
invention include, singly or a combination thereof, cellulosic materials
such as cellulose gum (carboxymethyl cellulose) and cation salts thereof,
including sodium, potassium, ammonium and calcium salts; polyuronic acids
such as soluble alginic said salt, pectins and cation salts thereof,
including sodium, potassium, and ammonium salts; and modified starches
such as oxidized starches and carboxylated starches, and cation salts
thereof, including sodium, potassium, ammonium and calcium salts. These
biodegradable materials pose no known environmental problems.
Part A is generally dispersed in at least one solvent, preferably water and
organic glycols with low toxicity, such as propylene glycol.
Gelatinous materials include gelatin, collagen, and salts thereof, or a
mixture of such materials. Materials such as these proteins are rapidly
degraded by environmental forces.
The polysaccharides which contain acid functional groups are included in
the range between about 0.1 percent and about 10 percent but preferably
between approximately 0.5 percent and about 2 percent. The gelatin
component is added in the range of about 0.5 percent and approximately 20
percent and the preferred range is approximately 0.5 percent and about 4
percent. The surfactant ranges between about 0.5 percent and about 20
percent and preferably between approximately 0.5 percent and approximately
4 percent. The solvent for part A includes a plurality of compounds in the
range of about 50 percent and about 99 percent where the water component
varies between about 25 percent and approximately 50 percent and the
organic component is preferably between about 25 percent and about 50
percent.
Part B is simply a solvent that has about 1% food color dye dissolved in
it. The solvent in part B is water, an organic glycol with low toxicity
such as propylene glycol, alkoxytriglycols, alkoxydiglycols or
hydroxyethyl pyrrolidone, or an aqueous mixture of such organic solvents.
The components are applied to the aircraft in a different manner than
previously disclosed for the aircraft antifreeze gel. The composition is
applied with modified Powermate Pressure Wash spray units (Coleman
Powermate, Inc., Kearney, Nebr.). Part A and part B solutions are placed
in carboys and placed above the spraying unit to gravity feed the
sprayers. Unlike the spraying method utilized above, part B is applied
prior to part A. Part B is simply attached to a high pressure unit which
will disperse the mixture in a fine mist to uniformly cover the lifting
surfaces of the plane to be covered. Thus the propylene glycol antifreeze
initially coats the plane immediately prior to foamed part A. The
application of component part A also varies from that previously described
in that higher pressures, e.g. up to 1200 psi, and spray rates, e.g. 1.75
gallon per minute, are preferred. In addition, the spray from the part A
wand is directed through a screen held in front of the spray tip to
produce a fine bubble foam. Alternatively, a commercially available
foaming machine would generate an even finer bubbled foam.
The foam is applied to the wings in a thickness range between approximately
one half inch and about six inches, but a thickness range between about
one inch and approximately two inches is generally preferred. Applying
part A as a foam presents several long term benefits. The foam adheres to
the wing due to its viscous nature and insulates the wing from moisture
condensing onto the wing due to the cold fuel in the aircraft. Due to the
very stable nature of the foam it provides a stable foam for a period of
up to about six hours. Any precipitation falling contacts the foam and as
the moisture works its way through the foam it dissolves the organic
antifreeze agents and lowers the freezing point of the water. By the time
the moisture reaches the wing itself, it has achieved antifreeze
characteristics and will not freeze to the metal.
The dye in the composition is visible to the eye or with the use of
ultraviolet light at night. As the moisture falls, the water extracts the
dye from the solution and the visibility of the dye decreases as the
amount of anti-icing protection decreases. The amount of dye or its color
can be calibrated to determine the safe level of protection before ice
formation becomes a serious safety hazard.
The invention as it is applied to the parts of aircraft as de-icers and
antifreeze is more specifically described in the embodiment in example 3.
All percentages are calculated on a weight percent basis.
EXAMPLE 3
______________________________________
Part A Part B
______________________________________
.5% cellulose gum
99% propylene glycol
2% gelatin 1% dye
2% lauryl sulfate
48% propylene glycol
47.5% water
______________________________________
Part A was prepared by heating approximately one liter of water to boiling.
About forty grams of gelatin (275 bloom) were added to the boiling water.
Before the solution cooled, approximately one liter of propylene glycol
was added to the above solution to make a combined volume of approximately
two liters. About ten grams of cellulose gum were added to the vigorously
stirred solution, noting that the viscosity of the solution increased as
the cellulose gum dissolved. This solution was stirred for a period of at
least about one hour or until the solution was clear, homogeneous and lump
free. Approximately forty grams of previously dissolved lauryl sulfate in
water were added to this solution.
The composition was applied with modified Powermate Pressure Wash spray
units (Coleman Powermate, Inc., Kearney, Nebr.). Part A and part B
solutions were placed in five gallon carboys and placed about two feet
above the spraying unit to prime and gravity feed the sprayers. Unlike the
spraying method utilized above, part B was applied to the surfaces
substantially immediately before part A by simply moving the two secured
spray wands in a motion so part B went on before part A. Part B was
attached to a high pressure unit which dispersed the mixture in a fine
mist to uniformly cover the lifting surfaces of the plane to be covered.
The propylene glycol antifreeze initially coated the plane immediately
prior to foamed part A. The application of component part A occured at a
back pressure of about 1200 psi and a spray rate of about 1.75 gallon per
minute. In addition, the spray from the part A wand was directed through a
90 mesh screen held about two inches in front of the spray tip to produce
a fine bubble foam.
The foam was applied to the wings in a thickness range between
approximately one inch and approximately two inches.
Thus there has been shown and described novel means for environmentally
sound antifreeze compositions and uses without ethylene glycol or alkaline
earth halides. The present invention fulfills all the objects and
advantages set forth above. It will be apparent to those skilled in the
art, however, that many changes, modifications, variations and other uses
and applications for the subject invention are possible. All such changes,
modifications, variations and other uses and applications which do not
depart from the spirit and scope of the invention are deemed to be covered
by the invention, which is limited only the claims which follow.
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